Cytokine production after influenza vaccination in a healthy elderly population

Influenza vaccination is less efficacious in the elderly than in the young. To characterize this age-related decrease in immune response to influenza vaccination, antibody and cell-mediated responses to influenza vaccine were assessed before immunization and 4 weeks after vaccination of a population of 270 healthy elderly individuals (mean age: 80.2 years) living in eight local continuing care retirement communities (CCRCs) and 30 young individuals (mean age: 27.8 years). The antibody titres produced against all three influenza strains increased significantly after vaccination in both the young and elderly (p < 0.0005); however, the young demonstrated significantly higher titres to all three strains than did the elderly (p < 0.03). Peripheral blood mononuclear cells (PBMC) cultured with influenza vaccine demonstrated significantly increased proliferation (elderly: p < 0.00005; young: p < 0.001) after vaccination, with proliferative responses in the young significantly higher than the elderly both before (p < 0.04) and after (p < 0.0005) vaccination. Similarly, IFN gamma production in these PBMC cultures increased significantly pre- to postvaccination in both young and elderly (young: p < 0.006; elderly: p < 0.00005), but the young produced more than the elderly both pre- and postvaccination (p < 0.0001). Following vaccination, PBMC production of IL-10 was higher in the young than in the elderly (p < 0.0015), while IL-6 production was comparable in both young and elderly individuals. Greater than 13% of the elderly population did not produce detectable IL-6, IL-10, or IFN gamma either before or after vaccination. The data show that the decreased cell-mediated and humoral responses to influenza vaccination of this healthy elderly population are accompanied by the production of lower levels of cytokines. A unique finding in this population of 270 healthy elderly was the association between a TH0 cytokine profile and intact immune responses to influenza vaccine. A similar relationship was not seen in the young.

Quantitative hydroxyl radical footprinting reveals cooperative interactions between DNA-binding subdomains of PU.1 and IRF4

Quantitative hydroxyl radical footprinting and fluorescence polarization measurements have been used to determine the dissociation constants (Kd) of complexes between the ets domain of the murine transcription factor PU.1 and three different DNA fragments. Two natural PU.1 binding sites, the SV40 enhancer site and the lambdaB motif of Iglambda2-4 enhancer, were used as well as the PU.1 binding site present in the crystallized PU.1-DNA complex. With the use of quantitative hydroxyl radical footprinting we obtained binding isotherms for individual protected nucleotides and contact sites on both strands of the DNA. Kd values of (1.53 +/- 0. 12) x 10(-)8 M were found for the lambdaB element, (3.60 +/- 0.65) x 10(-)8 M for the SV40 enhancer site, and (2.28 +/- 0.27) x 10(-)8 M for the sequence used in the crystal structure. In addition, the binding of a second protein, the DNA binding domain of IRF4, to the lambdaB site by itself and in the presence of PU.1 was analyzed. The IRF4 DBD shows three footprints on the TTCC strand and one footprint on the GGAA strand of the lambdaB element. The dissociation constant for the binary IRF4 DBD-lambdaB complex equals (5.59 +/- 0.60) x 10(-)7 M. The Kd value of the IRF4-lambdaB interaction is reduced by a factor of 5 in the presence of two different DNA-bound PU.1 protein constructs, PU.1 DBD and a PU.1 construct containing the PEST domain (PU.1-PEST). A similar decrease of the Kd value was observed for the binding of PU.1-PEST in the presence of DNA-bound IRF4 DBD demonstrating a cooperative interaction between the PU. 1-PEST and IRF4 DBD. On the basis of the hydroxyl radical footprints in the ternary PU.1/IRF4/lambdaB complex, a model for the interactions between the two proteins and the lambdaB site was developed. The DNA binding domains of both proteins bind the DNA in the major groove with potential protein-protein interactions near the intervening minor groove.

Hydroxyl radical footprinting of DNA complexes of the ets domain of PU.1 and its comparison to the crystal structure

Hydroxyl radical footprinting has been used to probe interactions in complexes between the ets domain of the murine transcription factor PU.1 and three different DNA restriction fragments, each containing one copy of the recognition sequence 5'-GGAA-3'. Two natural PU.1 binding sites, the SV40 enhancer site and the lambdaB motif of Ig lambda2-4 enhancer, were used as well as the PU.1 binding site present in the crystallized PU.1-DNA complex [Kodandapani, R., Pio, F., Ni, C.-Z., Piccialli, G., Klemsz, M., McKercher, S. R., Maki, R. A., and Ely, K. R. (1996) Nature 380, 456-460]. The footprints obtained for the three different DNA sequences are almost identical. The extent of contact with the protein was monitored for every base in the complex. Two concentration-dependent cleavage sites on the complementary TTCC strand are evidence of a specific interaction between PU.1 and the DNA. Two more protection sites and a hypersensitive cleavage site on the GGAA strand were observed. Although these data confirm the global structure of the PU.1-DNA complex as suggested by crystallography, the footprinting data reveal differences between the protein-DNA contacts in solution and in the crystal state. An additional interaction site not present in the crystal structure was observed by hydroxyl radical footprinting.

The treatment of severe hyponatremia

Severe hyponatremia may be chronic (days) or acute (hours), symptomatic or asymptomatic. Severe chronic symptomatic hyponatremia (serum sodium concentration < 110 to 115 mM/liter) occurs most commonly in the syndrome of inappropriate antidiuretic hormone secretion (SIADH). The treatment of this hyponatremia is a challenge to practicing physicians, in part because an overly rapid correction of hyponatremia may cause brain damage. The latter sometimes takes the form of central pontine myelinolysis (CPM). On the basis of available clinical and experimental literature, the rate of correction of this symptomatic hyponatremia should be no more than 0.5 mM per liter per hour, and the initial treatment should be halted once a mildly hyponatremic range of the serum sodium concentration has been reached (approximately 125 to 130 mM/liter). In contrast, severe chronic asymptomatic hyponatremia may be treated sufficiently by a fluid restriction. On the other hand, severe symptomatic acute hyponatremia should be treated promptly and rapidly, using hypertonic saline, to initially reach a mildly hyponatremic level.

Severe hyponatremia after transsphenoidal surgery for pituitary adenomas

Severe hyponatremia has been described after elective surgery with subsequent permanent brain damage. Other authors, however, have noted that morbidity and mortality rates of severe hyponatremia have been greatly overestimated. We retrospectively examined 19 patients (8 male, 11 female) who developed severe hyponatremia (100 to 124 mmol/liter) after transsphenoidal surgery for pituitary adenomas. Eight patients had hormonally inactive adenomas, 5 ACTH-secreting adenomas, 2 GH-secreting adenomas and 4 prolactin-secreting adenomas. The mean age of the patients was 47.5 years, with a range from 16 to 71 years. The mean preoperative serum sodium level was 137.8 mmol/liter. The timing of hyponatremia showed two different patterns. Five patients developed early postoperative hyponatremia (mean 114.0 mmol/liter +/- 4.85) and 14 patients showed the lowest mean serum level one week after surgery (118.1 mmol/liter +/- 6.86). Patients with early hyponatremia had fewer and less severe symptoms than patients with delayed hyponatremia. None of the patients developed seizures or a demyelination syndrome. Despite severe degree of hyponatremia for most of our patients treatment with water restriction and oral sodium supplementation was sufficient.

[Sudden hyponatremia with unconsciousness. Case report and brief overview of the syndrome of inadequate antidiuresis (SIAD or Schwartz-Bartter syndrome]

A sixty-six year old female was admitted to the hospital with an incomplete hemiparesis on the left side combined with a short episode of unconsciousness. According to her husband's account she had a seizure. Relevant laboratory measurements: plasma sodium concentration 113.9 mmol/l, plasma concentration of ADH 10.3 pg/ml, urine sodium concentration 44.4 mmol/l. The plasma concentrations of creatinine and urea were within normal limits. The working hypothesis was SIAD (syndrome of inappropriate antidiuresis) or Schwartz-Bartter-syndrome. The patient was treated immediately with water restriction (500-1000 ml/day), furosemide and i.v. replacement of urinary sodium losses by 3% NaCl. The analysis of cerebrospinal fluid showed pleocytosis and increased concentrations of immunoglobulins G and M. Serological diagnosis was positive for antigen of varicella-zoster virus. These observations were thought to be compatible with a diagnosis of SIAD in the setting of encephalitis. Under water restriction, infusion of 3% saline, treatment with loop diuretics and aciclovir (3 x 750 mg daily) the neurological function returned to normal within 2 days. A standard oral water load on the 14th hospital days showed a return to a normal water metabolism.

[Aquaretic drugs--a new therapeutic principle in treatment of hyponatremia?]

The antidiuretic hormone (vasopressin) is involved, either directly or indirectly, in the pathogenesis of almost all forms of hyponatremia. This means that blockage of the ADH effect at the renal ADH receptor represents a rational approach in the treatment of hyponatremia, in particular in difficult-to-treat and symptomatic forms. Recently, orally absorbable, non-peptidergic competitive ADH antagonists (aquaretics) have been introduced, which bind with high affinity to renal ADH receptor subtypes. Initial investigations in humans show that the substance is well tolerated. Numerous studies on patients with hyponatremia of varying genesis have since been started. It is to be expected that the availability of this new dass of substances will result in marked improvements in the treatment of acute and chronic forms of hyponatremia.

[Sports activity and risk of arthrosis]

Although the potential risk of exercise-induced osteoarthrosis (OA) of weight-bearing joints such as hip, knee and ankle is of great public health importance, very little is known about it. One reason for this lack of knowledge may be the multifactorial etiology of degenerative joint disease, rendering it difficult to quantify the effect of an isolated factor such as exercise and sport on OA. The present review summarizes the current state of knowledge. Recent epidemiologic studies consistently find a slight increase in the risk of OA of hip and knee in those exercising very heavily, which is more marked in ball games than in endurance disciplines. Several epidemiologic studies (including the methodologically best ones) have investigated the effect of jogging on OA risk. They find that extremely active runners may be exposed to increased risk of OA of hip and knee that should not be totally disregarded. On the other hand, regular jogging in middle age is likely to help maintain physical function. A typical finding is that in former athletes the radiologic signs of degenerative joint disease appear to correspond more to the hypertrophic type (with osteophytes and subchondral sclerosis) than the destructive type (with joint space narrowing). This observation raises the question of the prognostic value of the radiologic signs observed in heavy exercisers. Accordingly, taking into account animal experiments and occupational studies as well, a slight increase in the risk of OA of weight-bearing joints due to very frequent and heavy exercise over many years cannot be entirely ruled out. However, for the majority of (less active) exercisers, recreational physical activity seems neither to increase nor decrease the risk of OA to any marked extent.

Hyponatremia: pathophysiology, differential diagnosis and new aspects of treatment

Hyponatremia is the most frequent electrolyte disorder in clinical medicine. It is usually attributable to primary vasopressin excess, causing the syndrome of inappropriate antidiuresis (SIAD), or to secondary vasopressin stimulation, involving a baroreceptor mechanism. The latter is regularly found in the hyponatremia of liver cirrhosis, cardiac failure and volume contraction. In the first kind of setting the concentrations of creatinine, urea and urate in plasma will be low because of the associated volume expanded state. In the second type of setting they will be elevated because of the circulatory compromise of these patients. The hyponatremia of SIAD may be treated by water restriction, furosemide and substitution of the inadvertent sodium losses by giving 3% NaCl. Baroreceptor hyponatremia is best treated by fluid restriction together with judiciously administered saline. In correcting severe chronic hyponatremia, the rate of correction should not exceed 1 mM/l/h and the corrected serum sodium concentration should not be higher than 130 mM/l. In the foreseeable future oral non-peptide oral vasopressin antagonists will become available. They are expected to become new tools for the treatment of hyponatremia.

Colicin M is inactivated during import by its immunity protein

Colicin M (Cma) displays a unique activity that interferes with murein and O-antigen biosynthesis through inhibition of lipid-carrier regeneration. Immunity is conferred by a specific immunity protein (Cmi) that inhibits the action of colicin M in the periplasm. The subcellular location of Cmi was determined by constructing hybrid proteins between Cmi and the TEM-beta-lactamase (BlaM), which confers resistance to ampicillin only when it is translocated across the cytoplasmic membrane with the aid of Cmi. The smallest Cmi'-BlaM hybrid that conferred resistance to 50 micrograms/ml ampicillin contained 19 amino acid residues of Cmi; cells expressing Cmi'-BlaM with only five N-terminal Cmi residues were ampicillin sensitive. These results support a model in which the hydrophobic sequence of Cmi comprising residues 3-23 serves to translocate residues 24-117 of Cmi into the periplasm and anchors Cmi to the cytoplasmic membrane. Residues 8-23 are integrated in the cytoplasmic membrane and are not involved in Cma recognition. This model was further tested by replacing residues 1-23 of Cmi by the hydrophobic amino acid sequence 1-42 of the penicillin binding protein 3 (PBP3). In vivo, PBP3'-'Cmi was as active as Cmi, demonstrating that translocation and anchoring of Cmi is not sequence-specific. Substitution of the 23 N-terminal residues of Cmi by the cleavable signal peptide of BlaM resulted in an active BlaM'-'Cmi hybrid protein. The immunity conferred by BlaM'-'Cmi was high, but not as high as that associated with Cmi and PBP3'-'Cmi, demonstrating that soluble Cmi lacking its membrane anchor is still active, but immobilization in the cytoplasmic membrane, the target site of Cma, increases its efficiency. Cmi delta 1-23 remained in the cytoplasm and conferred no immunity. We propose that the immunity protein inactivates colicin M in the periplasm before Cma can reach its target in the cytoplasmic membrane.

Paracrine renal endothelin system in rats with liver cirrhosis

1. Liver cirrhosis was induced in rats by CCl4 administration. We analysed the expression of endothelin receptor subtypes in the renal cortex and medulla using Scatchard analysis and receptor autoradiography, and measured plasma as well as renal-tissue endothelin-1 concentrations using a specific radioimmunoassay. Furthermore, we analysed the effects of the non-selective (A/B) endothelin receptor antagonist, bosentan (6 and 100 mg kg-1 day-1) on mean arterial blood pressure, water and sodium excretion and glomerular filtration rate. 2. Our study revealed an overexpression of the endothelin B receptor (ETB) in the renal medulla of rats with liver cirrhosis (Cir: 2775 +/- 299 fmol mg-1; Con: 1695 +/- 255 fmol mg-1; n = 8; means +/- s.d., P < 0.01), whereas the density of ETB in the cortex and the endothelin A receptor (ETA) in the cortex and medulla were similar in both cirrhotic and control rats. Receptor autoradiography showed that the upregulation of medullary ETB in cirrhotic rats was due to an upregulation of ETB in the inner medullary collecting duct cells. 3. The tissue endothelin-1 concentrations were increased in the renal medulla of cirrhotic rats (Cir: 271 +/- 68 pg g-1wet wt.; Con: 153 +/- 36 pg g-1 wet wt., n = 8; means +/- s.d., P < 0.01). 4. The glomerular filtration rate was slightly decreased in cirrhotic rats but not altered after bosentan treatment in either cirrhotic or control rats. Bosentan decreased sodium excretion to a similar extent in both cirrhotic and control rats, whereas water excretion was significantly reduced by both dosages of bosentan in cirrhotic rats only (Cir + vehicle: 12.5 +/- 0.62 m day-1, Cir + 6 mg kg-1 day-1 bosentan: 8.6 +/- 1.0 ml day-1; Cir + 100 mg kg-1 day-1 bosentan: 7.4 +/- 0.6 ml day-1; n = 10; means +/- s.e.mean). 5. We therefore suggest that the upregulation of the medullary ETB in cirrhotic rats is involved in the regulation of water excretion in rats with CCl4-induced liver cirrhosis.

Lithium induced polyuria and renal vasopressin receptor density

BACKGROUND

Lithium, a drug frequently used for treatment of affective disorders, is known to cause a vasopressin-resistant state, leading to polyuria and polydipsia. It has been suggested that lithium interacts with the renal V2-vasopressin receptor. Detailed studies on the influence of lithium on the AVP receptor, however, have so far been difficult due to the lack of a suitable radioligand with high specific activity and high affinity.

METHODS

Using 125I-[8-(p-(OH)-phenylpropionyl)]- LVP, we studied the effects of lithium on V2-vasopressin receptors in male Sprague-Dawley rats and LLC-PK1 cells. Rats, having free access to water, were orally treated with 10 mg lithium/100 mg b.w./day or placebo for 10 days. Scatchard analysis was performed using membranes prepared from homogenized renal papillae.

RESULTS

Lithium caused significant polyuria and an impaired renal concentration capacity after water deprivation. Binding studies showed no effect of lithium on binding affinity KD (0.98 +/- 0.21 nmol/l vs. 0.86 +/- 0.15 nmol/l (Li) (n.s.). Receptor density, however, significantly decreased from 130 +/- 12.3 nmol/kg protein in controls (n = 8) to 101.7 +/- 13.4 nmol/kg protein (n = 8), (P < 0.05). Plasma osmotically and AVP were not significantly altered by lithium treatment. Vasopressin receptor density on LLC-PK1-cells, a pig renal cell line, was not changed by preincubation with lithium (312 +/- 22 nmol/kg vs. 329 +/- 25 nmol/kg (Li) (n = 6, n.s.).

CONCLUSIONS

The decrease of AVP-receptor density in vivo might be related to vasopressin resistance, either primary, or secondary to other factors, e.g. actual water transport.

Adult immunizations

New vaccines have been licensed for hepatitis A, varicella, and typhoid. This paper reviews these vaccines and their recommended uses in adults. Special attention is given to a new national policy establishing age 50 years as a time for review of preventive health measures with emphasis on evaluating risk factors that indicate a need for pneumococcal vaccine and the initiation of annual influenza immunization.